Resistance unit



C. R. ENGLUND.

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I APPLICATIO lLED APR. 18. 19I9. I 1,347,900. Patented July 27, 1920.

In van for: Carl R. E ng/und UNITED ST TES PATENT OFFICE.

CARL R. ENGLUND, OF EAST ORANGE, NEW JERSEY, ASSIG NOR TO' WESTERN ELECTRIC COMPANY, INCORPORATED, 013 NEW YORK, N. Y., A CORPORATION OF NEW YORK.

' RESISTANCE UNIT.

1,347,900. v Application filed April 18,

I concise, and exact description.

This invention relates to resistance units but more particularly to such units WhlCh are adapted to be used in alternating current measurements.

The object of this invention is the provision of a resistance unit wound in such a manner'as to -be substantially non-reactive under all conditions.

In radio telephony, radio telegraphy, and such other apparatus in which currents of high frequency are employed, it is very desirable that a resistance unit be provided which will not be affected by stray or inductive currents from other apparatus mounted in close proximity thereto, as well as being non-reactive in itself. It is, of course, impossible to construct resistance units which have zero reactance but a high degree of non-reactance may be attained.

' It has been found that in cases where currents of high frequency are employed that the effective capacitance of the resistance unit is the least effective when the unit is wound in a single layer solenoid.\ The inductance however, predominates and it has been found that the practical limit in the way of reducing the inductance is reached when adjacent-turns of the-winding are reversed in direction.

In accordance with the object of the invention, there is provided a resistance unit in which the conductor forming the winding is wound in a single layer and arranged in such a manner that the inductive effect of currents from other portions of the winding is minimized and the external field surrounding such a coil is substantially reduced to zero. This feature is accomplished by forming a resistance coil in which each of the turns thereof is wound in opposite sense to its neighbor.

The space occupied by such a coil is an important factor, and it is, therefore, essential that the conductor forming the winding thereof be wound as compact as possible,

arrangement.

' Specification of Letters Patent. Patented July 27, 1920.

1919. Serial No. 290,989.

and still allow sufficient space between the turns, thereby eliminating any danger from the insulation breaking down. The forming of such a coil as herein specified, not only provides a compact coil but also one that is'neat in appearance and easy to-manufacture.

It is thought that a more definite understanding of the invention will be had by reference to the following description taken in conjunction with the accompanying drawing, in which Figure 1 shows a resistance unit constructed in accordance with one embodiment of the invention. Fig. 2 shows an arrangement of a plurality of such resistance units combined with a switching In Fig. 1 there is shown a developed view of a coil, the winding of which maybe wound on any style of rod, bar or toroidal shaped insulator. The method of winding consists in laying up the individual turns, so that every turn is laid up in opposite sense to its neighbor. This is accomplished by first throwing the loop 1 over the bar or insulator in one direction, and then throwing the turn 2 over in the opposite direction. The portion of the conductor formmg the loop 2 is brought over that forming the loop 1 and then laid on in the reverse direction to that of loop 1. In this way the turns may be stacked up and the wire pulled tight thereby maintaining the turns in position. As a result of this method of forming the coil, the loops forming the coil are thrown from right to left or v1ce Versa, that is the second loop is turned through an angle of 180 before laying it on the support, as is apparent from an inspection of Fig. 1. It is thus evident that the direction of current flow in two adjacent turns of such a winding is opposite so that the inductive effect thereof is practically eliminated. The external field surrounding such a coil wound in this manner is also reduced to substantially zero for the same reason.

Referring now to Fig. 2 the rod 3 for supporting the coils 4, 5, 6, l and 8 is secured to the standards or supports 9 by means of the screws 10. The standards 9 carry a plate 11 to which is secured the contact studs 12, one end of which extends through the plate 11, The lower ends of the studs carry the nuts 18 and 19, the former being adapted to securely hold the contact stud in posit on, the latter serving as a means for attaching the terminals of the various coils thereto. These contact studs are constructed of conducting material, and permit the spring contact member 13 to easily ass from one contact stud to another. he spring contact member 13 is secured to the arm 14 which is adapted to be revolved about the pin 15 as a center. Binding posts 16 and 17 are provided whereby other apparatus may be associated therewith, as wellasforming a -means for connecting a source of current supply thereto.

It is thus evident that by prov1d1ng a plurality of such coils, that the reslstance 1n the circuit may be varied to any desired value within the range with wh1ch it is adapted to be used, as the contact arm 14 may be revolved to any desired position, thereby cutting in or out of the circuit any or all of the coils depending upon the manner in which the coils are connected. The coils may be connected'in series, or they maybe grouped in any arrangement wh1ch Wlll give the most satisfactory results and it is therefore not intended to limit the invention to any particular form of connecting the coils.

It is, of course, obvious that there are various methods which may be used for supporting the coils other than that which is shown in Fig. 2 without departing from the spirit of the invention.

What is claimed is:

1. A method of forming a coil which consists in forming a series of closed loops and laying each successive loop on a support in a direction opposite to that of the previous loop and interlocking each successive loop with said previous loop.

2. A method of forming a coil which con-- sists in forming a loop in a continuous conductor and laying it on a support and forming a similar loop and twisting the same through 180 before laying it on the same support adjacent the first loop.

3. An electrical coil comprising a continuous conductor laid on a support in alternately oppositely directed interlocked concentric loops.

4. An electrical coil comprising a continuous conductor laid on a support in a series of oppositely directed interlocked loops with the interlocking portions in alinement.

5. An electrical coil comprising a continuous conductor formed in a series of alternately oppositely directed interlocked concentric loops a ording a current path reversing in direction with each loop.

In witness whereof, I hereunto subscribe my name this 15th da of April A. D., 1919.

CA L R. ENGLUND. 

